Push-pull-actuated radial resonator



Patented Nov. 19, 1929 MILLER REESE`HUTCHISON, 0F VJEST ORANGE, NEW JERSEY, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 ACOUSTIC PRODUCTS COMPANY, F 'NEW YORK, N. Y., AL'O'R- PQRATION 0F DELAWARE PUSH-PULL-CTUATED RADIAL RESONATQR Application tiled August 4, 1927. Serial No. 210,551.

The invention relates in general to acoustic apparatus, and more particularly to a loud speaker or sound reproduc-er in which a column of air is set into vibration by a mechanical diaphragm or piston.

The ideal diaphragm for. use with a loud speaker is a rigid piston acting in a cylinder in such manner that 'there is no friction between the piston and the cylinder and yet the joint therebetween is sound tight. rlhis condition, of course, is impossible to produce, although it may be closely approached if p much care is ta'ken. However, this type of ceiver.

diaphragml is not entirely satisfactory for commercial purposes. The usual plane flexible diaphragm, on the other hand, is free from sound leakage and frictional binding but has the disadvantage of dividing up into one or more nodal and ventral parts, vibrating at different frequencies. This action is very complicated and under certain conditions causes undesirable characteristics in the loud speaker especially in those of the multiple bhorn type.

According to the invention these disadvantages are overcome in a novel and eiificient manner, and a loud speaker is provided which renders tones of exceptional urity and reproduces music with utmost delity.

According to the invention, a plurality of horns or pipes of different lengths are provided, each being resonant to a dierent note preferably of the chromatic scale. These pipes or horns may be arranged in curved and nested relation to save space and to present an ornamental and decorative appearance, or they may be arranged in any other desired way. Each horn communicates with a common chamber, connected to which is a rigid diaphragm preferably of the cone type and operated by a push-pull electromagnetic re- The diaphragm is attached to the horns by a resilient and elastic joint and moves en masse in response to vibrations communicated thereto. If desired, the cone may be suitably reenforced by strengthening ribs. Two cones may be used instead of one, the conesbeing disposed in opposed relation, and

each being operated by its own electromagnetic push pull receiver.

Various other features and advantages of the invention will be apparent from the foln lowing particular description and from an inspection of the accompanying drawings.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner of its organization may be better understood by referring to the following description taken in connection with the accompanying drawings forming a part thereof, in which Fig. l is a side elevation, parts being broken away, of a loud speaker according to the invention;

llig. 2 is a section on the line 2 2 of Fig. l, the push-pull receiver being indicated diagrammatically;

Fig. 3 illustrates a slight modification of Fig. 2;

Figs. 4 and 5 show slightly modified forms of the diaphragm; and

Fig. 6 is a modification illustrating the use of opposed cone diaphragms.

ln the following description and in the claims parts will be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring now to the drawings, and more particularly to Figs. l and 2, the loud speaker or sound reproducer comprises a horn member l made up of a pair of plates 2 and 3 having a generally circular outline. One of the plates 2 has an opening 5 therein off centre. Extending between the plates are a plurality of wallsfi extending from the opening to the periphery of the plates, the walls being preferably in the form of a logarithmic spiral and in nested relation to save space. The plates and Walls form a plurality of horns or pipes 6 of different lengths and open at their outer ends, each pipe being tuned to resonate some particular note, preferably one of the notes of the chromatic scale. Any number of horns may be provided, there is a stylus rod 10 extending to an energy transfer device 11 which may be any suitable type of well known push-pull electromagnetic receiver. The stylus rod 10 may be connected to the apex of the cone in any desired manner such as by solder or by nuts (not shown). The common sound chamber 12 communicating with the several horns 6 should be of as small cubic content as possible so as not to have a natural period Within the range of audibility.

Referring now to Fig. 3, the construction shown is similar to that shown in Figs. 1 and 2, parts being denoted by similar reference characters. The walls 4 are provided with angular extensions 13 extending close to the surface of the cone to reduce the chamber 12 to the smallest possible size and thereby improves the operating characteristics of the loud speaker.

Referring now to Figs. 4 and 5, if desired, the cone diaphragms shown in Figs. 1, 2 and 3 may be provided with elemental strengthening ribs 14 extending from the apex to the radial base flange 8 on the inside of the diaphragm to insure utmost rigidity throughout the body of the cone. The stylus rod 10 is connected to the apex of the cone in any desired manner.

Referring now to Fig. 6, the horn arrangement is similar to that described above but both lates 22 and 23 are provided with a cone iaphragm 27 having aradial flange 28 at its base and having a stylus rod 30 suitably connected to the apex thereof, the stylus rod extending outwardly to an electromagnetic push-pull receiver 31, similar to that used in Fig. 2.

Each cone diaphragm 27 may be connected to its plate 22 or 23 by a sponge rubber washer or gasket 29Ibeing cemented respectively to the plates and to the radial flange 28 of the cone diaphragm. The cone diaphragms extend inwardly, their apices being disposed in close relation. The walls 24 are provided with angular projections 33v which closely lit the cone diaphragms allowing merely enough clearance for the movement of the cone diaphragms. This construction cuts down the cubic content of the common sound chamber 32 to a minimum.

In Figs. 1 to 5 inclusive, when electric currents having sound waves impressed thereon traverse the windings of the receiver 11, they cause the cone diaphragm 7 to'vibrate in accordance with the electric currents en masse or as a unit, all the movement being taken up `by the sponge rubber washer or gasket 9. Thus it will be seen that the sponge rubber washer or gasket forms both an elastic and sound-tight joint. As the cone diaphragm vibrates, the sound Waves will be propagated at an angle of 45 degrees to the surface of the cone or in a direction parallel with the plane of the horns.

In the form shown in Fig. 6, the receivers 31 will be connected in such relation that the cone diaphragms 27 will approach and withdraw from each other simultaneously, causing alternate compressions and rarefactions. In this case also the sound waves will be propagated at an angle of 45 degrees from the surface of the cones, the direction being in the plane of the horns.

Thus a loud speaker has been provided which will give faithful and pleasing reproduction of electrical sound energy impressed upon the receiver. The diaphragms are rigid 4and move as a unit in accordance with the notes impressed thereon by the receiver. Each note will be resonated by some particular horn which is tuned either to the note itself or to a fundamental of which the note is a harmonic or overtone. It will be understood that the horns respond quite readily to the overtones or harmonics of the fundamleptal in addition to the fundamental itse The cone diaphragm moving as a unit in response to the acoustic variations, has many of the advantages, both of a simple piston and of a simple flexible diaphragm in addition to many special advantages inherent in its construction. In a diaphragm of the simple flat flexible type, the movement of the d1aphragm is very complicated, since the diaphragm moves not only as a unit but it also breaks up into one or more nodal and ventral parts. This complicated action in some cases causes undesirable characteristics in the loud speaker. On the other hand, in the case of the cone diaphragm the fiexible or yielding washer allows unitary movement of the diaphragm without sound leakage and without any substantial binding or resistance, and since the cone diaphragm vibrates en masse, its action is comparatively simple.

The use of the rigid cone diaphragm with the multiple resonating horns rovides a loud speaker having particularly faithful sound reproducing characteristics which produces remarkably clear tones throughout the entire audible range.

While certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will be understood that various omissions, substitutions and changes in the forms and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is 1. In acoustic apparatus, a hollow casing, a plurality of pipes communicating therewith, each pipe resonating a different note, said casing having an opening, a rigid cone diaphragm disposed over said opening, a yieldable member between saidY diaphragm and casing making a sound proof and yieldable joint, a stylus connected to the apex of said diaphragm, and actuating means having operative relation with said stylus.

2. In acoustic apparatus, a hollow casing, a plurality of pipes communicating therewith, each pipe resonating a different note, said casing having an opening, a rigid diaphragm disposed over said opening, a yieldable member between said diaphragm and casing, and a push pull receiverhaving operative relation with said diaphragm.

3. In acoustic apparatus, a casing, a plurality of pipes communicating with said casing, each pipe resonating a diderent note, said casing having an opening, a sponge rubber washer cemented around said opening, a cone diaphragm having a radial base flange cemented to said washer, a plurality of strengthening ribs extending from the apex of said diaphragm to said flange, said ribs being disposed on the inside of said cone diaphragm, the apex of said diaphragm extending within said casing, a stylus rod connected to said apex and actuating means operatively connected to said stylus rod.

4. Inacoustic apparatus, a casing, a plurality of pipes communicating with said casing,l

each pipe resonating a different note, said casing having an opening, a soft resilient member secured around said opening, a cone diaphragm having a radial base flange secured to said member, the apex of said diaphragm extending within said casing, a stylus rod connected to said apex and extending through said opening, and actuating means operatively connected to 'said stylus rod.

5. In acoustic apparatus, a pair of first and second plates, said first plate having an opening, a plurality of nested curved walls connecting said plates and extending from said opening to the outer edges of said plates and forming a plurality of pipes of different lengths each resonating a different note of the chromatic scale, a sponge rubber washer cemented to said first plate aroundthe opening therein, a cone diaphragm having a radial base flange cemented to said washer, a'plurality of strengthening ribs extending from the apex of said diaphragm to the flange thereof and disposed within the diaphragm, said walls having angularI projections extending close to said diaphragm, said diaphragm havoutwardly, and actuating means connected to said stylus.`

6. In acoustic apparatus, a pair of first and second plates, said first plate having an opening, a plurality of walls connecting said plates and extending from said openlng to the outer edges of said plates and forming n plurality of pipes of differentlengths each resouating a different note, a yieldable washer secured to said plate around the opening therein. 'a cone diaphragm having a radial base flange secure'd to said washer, said walls having anguplates and extending outwardly from sai-dY opening forming a plurality of horns, a cone diaphragm disposed over said opening and between said plates, said walls having angular projections extending close to said diaphragm, and energy transfer means having operative connection with said diaphragm.

8. In acoustic apparatus, a hollow casing. a

plurality of pipes communicating therewith,

each pipe resonating a different note. said casing having opposed openings, a rigid diaphragm disposed over each opening, a yieldable joint between each diaphragm and said casing, each diaphragm having operatively connected thereto an energy transfer device. 9. In acoustic apparatus, a hollow casing, a plurality of pipes communicating therewith, each pipe resonating a different note, said casing having opposed openings, a cone diaphragm disposed in each opening, the apices of said diaphragm being in close relation, a stylus connected to the apex of each diaphragm and extending outwardly, and epelrgy transfer meansconnected to said s y 1.

10. In a loud speaker, a pair of plates each having an opening, a plurality of nested, curved, walls connecting said plates and extending from said openings to the outer edges of said plates and forming a. plurality of pipes of different lengths each resonating a different note of the chromatic scale. a sponge rubber washer cemented to each plate around the opening therein, a cone diaphragm having aradial base flange cemented to each said washer, a plurality of strengthening ribs extending from the apex of each diaphragm -to the flange thereof and disposed within the diaphragm, said diaphragms extending towards each other, the apices of said diaphragme being disposed in close relation, said walls having angular projections extending into the space between said diaphragms and close thereto, each diaphragm having a stylus rod secured to its apex and extending outwardly, and actuating means connected to each st lus.

11. n a loud speaker a pair of plates, each having an opening, a pzlurality of walls con- 5- necting said plates and extending from said openings to the outer edges of said plates and forming a plurality o pipes of different lengths each resonating a different note, a. yieldable Washer secured to each plate around 10 the opening therein, a cone diaphragm having a radial base {iange secured to each said Washer, said diaphragms extending towards each other, the apices of said diaphragms being disposed in close relation, each da# 15 pbragm having a stylus rod secured to its apex and extending outwardly, and energy transfer means connected to each stylus.

Signed at New York, in the county of New York and State of New York, this 2d day of 20 August, A. D. 1927.

MILLER REESE HUTCHISON. 

